The present invention generally relates to a differential axle assembly wherein a differential gear set is supported within an axle housing. More specifically, the present invention relates to a differential axle assembly wherein the differential pinion gears are supported directly by a ring gear, thereby eliminating the need for a differential housing to support the differential gear set.
In an automotive vehicle, a differential gear assembly is used to transfer power from a rotating drive shaft to the axles and wheels of the vehicle. The rotating driveshaft of the vehicle is attached to a hypoid pinion gear, which engages a hypoid ring gear which is typically mounted onto a differential housing. The pinion and the ring gears are adapted to transfer rotation from the drive shaft to the differential housing such that the differential housing rotates perpendicular about the vehicle""s z-axis, about which the driveshaft rotates. Within the differential housing, the ends of the axles of the vehicle are supported and connected to the differential housing through a differential gear set, such as a bevel differential gear set. Thus, the hypoid pinion and the ring gear set allow the driveshaft to rotate the differential housing in a direction perpendicular to the vehicle""s z-axis, whereby the differential gear set rotates the axles of the vehicle to drive the wheels of the vehicle.
Typically the differential gear set includes a pair of side gears which are attached directly to the axles, and a pair of pinion gears which intermesh with the side gears. Most commonly, the pinion gears are supported by a pinion shaft which extends across the differential housing. The pinion gears are allowed to rotate on the pinion shaft thereby allowing the vehicle axles to rotate relative to one another. The rotational load is thus transferred from the driveshaft to the pinion gear, to the ring gear, through the differential housing and to the pinion shaft. Therefore, the differential housing must be designed with enough structural integrity so as to support the loads being transferred. The required strength, however, typically requires a relatively large differential housing which is expensive and heavy.
Thus, there is a need for a differential axle assembly with a differential gear set, wherein the hypoid ring gear and the differential side gears are supported directly by the axle housing, and the pinion gears are supported directly by the hypoid ring gear, thereby eliminating the differential housing and allowing the differential axle assembly to be designed with less structural size and weight.